[PATCH] [144/275] p54pci: update receive dma buffers before and after processing

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Christian Lamparter <chunkeey@xxxxxxxxxxxxxx>

commit 0bf719dfdecc5552155cbec78e49fa06e531e35c upstream.

Documentation/DMA-API-HOWTO.txt states:

"DMA transfers need to be synced properly in order for
the cpu and device to see the most uptodate and correct
copy of the DMA buffer."

Signed-off-by: Christian Lamparter <chunkeey@xxxxxxxxxxxxxx>
Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
 drivers/net/wireless/p54/p54pci.c |   14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

Index: linux-2.6.35.y/drivers/net/wireless/p54/p54pci.c
===================================================================
--- linux-2.6.35.y.orig/drivers/net/wireless/p54/p54pci.c	2011-03-29 22:51:09.343484092 -0700
+++ linux-2.6.35.y/drivers/net/wireless/p54/p54pci.c	2011-03-29 23:03:01.264267821 -0700
@@ -199,6 +199,7 @@
 	while (i != idx) {
 		u16 len;
 		struct sk_buff *skb;
+		dma_addr_t dma_addr;
 		desc = &ring[i];
 		len = le16_to_cpu(desc->len);
 		skb = rx_buf[i];
@@ -216,17 +217,20 @@
 
 			len = priv->common.rx_mtu;
 		}
+		dma_addr = le32_to_cpu(desc->host_addr);
+		pci_dma_sync_single_for_cpu(priv->pdev, dma_addr,
+			priv->common.rx_mtu + 32, PCI_DMA_FROMDEVICE);
 		skb_put(skb, len);
 
 		if (p54_rx(dev, skb)) {
-			pci_unmap_single(priv->pdev,
-					 le32_to_cpu(desc->host_addr),
-					 priv->common.rx_mtu + 32,
-					 PCI_DMA_FROMDEVICE);
+			pci_unmap_single(priv->pdev, dma_addr,
+				priv->common.rx_mtu + 32, PCI_DMA_FROMDEVICE);
 			rx_buf[i] = NULL;
-			desc->host_addr = 0;
+			desc->host_addr = cpu_to_le32(0);
 		} else {
 			skb_trim(skb, 0);
+			pci_dma_sync_single_for_device(priv->pdev, dma_addr,
+				priv->common.rx_mtu + 32, PCI_DMA_FROMDEVICE);
 			desc->len = cpu_to_le16(priv->common.rx_mtu + 32);
 		}
 
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